1. Field of the Invention
The present invention relates to a method of producing heat with use of microwaves capable of directly producing the heat from an article to be heated by irradiating the article with microwaves thereonto.
2. Description of the Prior Art
Conventionally, a heating apparatus for applying china-painting on an article such as pottery and glass containers, etc., bakes the article at high temperature in a baking furnace in a factory of manufacturing it, and hence it requires an exclusive calcining furnace capable of being raised to a high temperature. Accordingly, it was impossible to find pleasure personally in baking the article for china painting.
In addition, in a heating apparatus for cooking, microwaves for irradiation are absorbed by a material to be cooked, which material is thus cooked by heat produced in itself. Thereupon, pottery and a glass container to house the material do not absorb the microwaves, so that the material is insufficiently heated, unlike direct heating, and it cannot be nice-smelling with the browned parts thereof. Moreover, the material to be cooked produces heat substantially due to collision of constituent molecules thereof with surrounding water molecules, and hence a material with a reduced content of water therein has bad efficiency to produce heat. Furthermore, the material cannot raise its temperature beyond the boiling point of the water contained therein and thereby cannot be cooked under strong heating.
Furthermore, in a microwave heating apparatus, an article to be heated disposed in the interior of a furnace body and heat insulated from the outside is directly irradiated with microwaves supplied exteriorly of the furnace for its heating. However, a heating apparatus of this type is adapted to directly heat an article to be heated. Accordingly, provided the article absorbs few microwaves, the conversion efficiency of irradiated microwaves becomes low. Thus, it was impossible to heat the article to desired high temperature. For example, to heat an article with little absorption of microwaves, such as pottery and the like, to high temperature for drying and calcining them, the apparatus could not work out effectively.
Furthermore, another microwave heating apparatus, e.g., a continuous type, is adapted in general to have its burning part for gas or liquid fuel disposed along the way in which the workpieces are fed. However, the pressure in its furnace is varied due to combustion gas produced upon combustion, so that adjustment of the temperature and the atmosphere in the furnace is difficult, as well as uniform heating over an article to be heated is impossible, and bad thermal efficiency is achieved owing to discharge of high temperature combustion exhaust gas.
To solve the drawbacks of the prior arts described above, it is an object of the present invention to provide a method of baking an article such as pottery and glass containers, etc., at high temperature for applying china painting thereonto with use of a domestic electronic oven.
Another object of the present invention is to provide a method of assuring ideal cooking by properly balancing, upon heating a material to be cooked and adjusting the degree of the heating in the domestic electronic oven, the radiation heat available from the glass vessel itself produced as a result of irradiation of microwaves thereonto and the heating of the material by microwaves directly acting thereon.
Still another object of the present invention is to provide a method of producing heat by microwaves with use of a simple structured furnace having a heat producing wall of higher microwave absorption efficiency, said wall enabling effective microwave heating.
To achieve the above objects, a method of producing heat with microwaves according to the present invention comprises:
(1) a method of producing heat adapted to mix or adhere a microwave absorption material and/or metal particles into or to a heating medium, and irradiate the heating medium with microwaves;
(2) a method of producing heat for cooking adapted to mix or adhere a microwave absorption material and/or metal particles into or to a heating medium mainly composed of a pottery raw material and irradiate the heating medium with microwaves;
(3) a method of producing heat for china-painting adapted to form a container to be housed in a domestic electronic oven with a heat insulating material, house an article to be subjected to china-painting, such as pottery and glass container, etc., in the container, arrange a heating medium with use of a microwave absorption material and/or metal particles as a main component on an inner peripheral wall part of the housing part in a confronting relation with a surface of the article subjected to china-painting, and irradiate the heating medium so provided with microwaves;
(4) a method of producing heat for cooking adapted to dispose a heating medium mainly composed of a microwave absorption material on an inner wall part of an outer casing comprising a heat insulating material, mount a container in a surrounding relation by the treating medium, put a cover on the container, and irradiate the heating medium with microwaves;
(5) a method of producing heat adapted to form a heating wall material with use of a material mainly composed of a microwave absorption material and metal particles via a heat resisting binder, construct a furnace wall of a furnace with use of the heating wall material while arranging a heat insulating material capable of transmitting microwaves on an outer periphery of a heating conductor, dispose a microwave irradiation equipment externally of the heat insulating material in a confronting relation with the heating wall material, and irradiate the heating wall material with microwaves from the microwave irradiation equipment;
(6) a method of producing heat adapted to arrange a tunnel-shaped furnace in the course of a conveyance path for a conveyor device serving to place on article to be heated thereon and convey the article, dispose a heating medium comprising a material mainly composed of a microwave absorption material on the inner wall surface of the tunnel-shaped furnace, arrange a microwave irradiation equipment for microwave irradiation externally of the furnace in a confronting relation with the heating medium, and irradiate the heating wall material with microwaves radiated from the microwave irradiation equipment.
According to the present invention, as described above, a heating medium effectively absorbs irradiated microwaves, whereby the heating medium reaches high temperature in a short time, while an article to be heated is heated by radiation heat in the same manner as being subjected to an open fire, and dried and baked. In addition, in baking a pattern applied on a surface of an article such as pottery and glass containers, the pattern is first drawn on the surface of the article with use of paints of a metallic oxide capable of producing a prescribed color when calcined, and the article is housed in the housing part and sealed. Then, with the heating medium irradiated with microwaves, the heating medium reaches high temperature in a short time, becomes red-hot, and radiates radiation heat. Hereby, the article is indirectly heated and hence the pattern is oxidized and baked on a base surface of the article. Moreover, upon cooking, various articles to be cooked are put in the heating apparatus, and with a heating medium irradiated with microwaves the heating medium reaches high temperature in a short time and becomes red-hot. Thus, the article is cooked by radiation heat from the heating medium under the same heating conditions as those in heating cooking by an open fire. Furthermore, in irradiating a heating wall material with microwaves from the microwave irradiation equipment after an article to be heated is housed in the furnace in opposition to the heating wall material, the heating wall material is irradiated with the microwaves through an insulating material, and hence the heating material absorbs the microwaves and produces heat, while carbon components contained in the metal particles likewise produce heat. Still more, the furnace is adapted to properly reflect microwaves existent therein to permit absorption efficiency thereof by microwave absorbing components to be increased and thereby the heating wall material to be heated in itself to high temperature. In addition, owing to the action of radiation heat by the microwaves so reflected in the furnace an article disposed in the furnace is indirectly heated. Furthermore, by employing the present heating apparatus as a conveyance and an equipment of continuously producing heat, a temperature gradient through the furnace body can arbitrarily set by adjusting the intensity of microwaves irradiated from the microwave irradiation equipment, whereby pottery, foods, and other articles to be heated can be dried or baked properly.
The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.